Centrifugal fan

ABSTRACT

A centrifugal fan includes a housing, a spiral impeller, a suction interrupting member. The housing includes a suction port and a discharge port. The housing further includes an outwardly curved cutoff portion at a side of the discharge port. The spiral impeller is coupled with a motor to suck air through the suction port of the housing in a rotation-axis direction and discharge the sucked air through the discharge port in a direction perpendicular to a rotation-axis. The suction interrupting member prevents air from being sucked into a neighborhood of the cutoff portion through the suction port.

CLAIM OF PRIORITY

This application claims the benefit of the earlier filing date, under 35 U.S.C. §119, to that patent application filed in the Korean Intellectual Property Office on Sep. 19, 2008 and assigned Serial No. 10-2008-0091954, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of centrifugal fans and more particularly, to a centrifugal fan for reducing noise generated in the area of a cutoff when air sucked into a scroll housing is discharged through a discharge port.

2. Description of the Related Art

Blowers or fans are devices that generate an air flow. Such a blower includes an impeller for generating an air flow and a housing for guiding the air flow generated by the impeller. Blowers may be selected according to their application and operation. Industrial blowers may be mainly used for various intake/exhaust systems, such as air conditioning systems or the like. The size of the blower may vary from small-sized computer cooling fans to large scale industrial blowers.

The blowers generally generate noise due to the non-uniform distribution of velocity and pressure when the sucked air is discharged. The noise generated in the blowers may occur by vibration of a structure or the air flow itself. Thus, research for reducing the noise generated by blowers is continuously being conducted.

FIG. 1A is a perspective view of a conventional computer cooling fan.

Referring to FIG. 1A, a computer cooling fan 100 includes a scrolling housing having an inner passage gradually spread and a fan cover 130 coupled to the scroll hosing 110. The scrolling housing includes a lower suction port 115 and a discharge port 114. The fan cover 130 includes an upper suction port 132. An inner passage of the scrolling housing 110 has a scroll-type spread pattern gradually spread toward the discharge port 114. The scrolling housing 110 further has a cutoff portion 111 for dividing an air flow. Moreover, the cooling fan 100 includes an impeller 120, rotatable coupled with a motor 121. The impeller 120 sucks external air through the suction ports 115 and 132 and discharges an internal air through the discharge port 114. The impeller 120 includes a plurality of curved blades 122, each having a predetermined length and width, extending radially toward the outside.

FIG. 1B is a plan view of the conventional computer cooling fan.

Referring to FIG. 1B, when power is provided for the motor 121 of the computer cooling fan 100, the impeller 120 is rotated. Since the impeller 120 is rotated, the external air is introduced through the lower suction port 115 of the scroll housing 110 and the upper suction port 132 of the fan cover 130. The introduced external air flows along the scroll-type spread passage of the scroll housing 110 through the curved blades 122. At this time, air having a dynamic pressure generated by the blades 122 of the impeller 120 is converted into air having a static pressure while passing through the scroll housing 110, and then, the air having the static pressure is discharged to the outside.

When the external air is sucked into the fan and then discharged, noise occurs because of the non-uniform distribution of velocity and pressure of the air flow. The noise includes discrete frequency noise and broad band noise. The discrete frequency noise is caused by blade passing frequency noise generated by an interaction between fluid passing through the scroll housing 110 and the blades 122 of the impeller 120. The broad band noise is caused by turbulent noise generated by a turbulent flow of air passing through the scroll housing 110 and the blades 122 of the impeller 120. In particular, the discrete frequency noise and the broad band noise are mainly generated at the neighborhood of the cutoff portion 111 of the scroll housing 110.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a centrifugal fan for reducing noise generated when air sucked into a scroll housing of the centrifugal fan is discharged through a discharge port.

Another object of the present invention is to provide a centrifugal fan for reducing noise generated at the neighborhood of a cutoff portion by controlling air sucked around the cutoff portion when air sucked into a scroll housing of the centrifugal fan is discharged through a discharge port.

In accordance with an aspect of the present invention, a centrifugal fan is provided. The centrifugal includes a housing including a suction port and a discharge port, a spiral impeller coupled with a motor to suck air through the suction port of the housing in a rotation-axis direction and discharge the sucked air through the discharge port in a direction perpendicular to a rotation-axis, and a suction interrupting member preventing air from being sucked into a neighborhood of the cutoff portion through the suction port, wherein the housing further includes an outwardly curved cutoff portion at a side of the discharge port.

In accordance with another aspect of the present invention, a computer cooling fan is provided. The computer cooling fan includes a housing including a suction port and a discharge port, a spiral impeller couple with a motor to suck air through the suction port of the housing in a rotation-axis direction and discharge the sucked air through the discharge port in a direction perpendicular to a rotation-axis, and a suction interrupting member preventing air from being sucked into a neighborhood of the cutoff portion through the suction port, wherein the housing further includes an outwardly curved cutoff portion at a side of the discharge port.

Other aspects, advantages and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above features and advantages certain exemplary embodiments of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

FIGS. 1A and 1B are a perspective view and a plan view, respectively, of a conventional computer cooling fan.

FIG. 2 is a perspective view of a cooling device including a computer cooling fan according to an exemplary embodiment of the present invention;

FIG. 3 is an exploded perspective view of a cooling fan according to an exemplary embodiment of the present invention;

FIG. 4 is a perspective view of an assembled cooling fan according to an exemplary embodiment of the present invention;

FIG. 5 is a perspective view of an assembled cooling fan according to an exemplary embodiment of the present invention;

FIG. 6 is a view illustrating a change of noise values measured over a frequency band of a conventional cooling fan; and

FIG. 7 is a view illustrating a change of noise values measured over a frequency band of a cooling fan according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description, with reference to the accompanying drawings, is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

It is to be understood that the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces.

By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. In the following description, detailed descriptions of well-known functions or constructions will be omitted since they would obscure the invention in unnecessary detail.

The present invention provides a centrifugal fan for reducing noise generated at the neighborhood of a cutoff when air sucked into a scroll housing is discharged through a discharge port.

In detailed descriptions of the present invention, although a computer cooling fan is used as an example, the present invention is not limited thereto and is applicable to other blower type devices with equal effect.

FIG. 2 is a perspective view of a cooling device including a computer cooling fan according to an exemplary embodiment of the present invention.

Referring to FIG. 2, a computer generally includes a cooling device 1000 that effectively cools heat generating components 160 integrated on a main board. The cooling device 1000 discharges heat generated from the heat generating components 160 such as a central processing unit (CPU), various chipsets, and a graphic card, which are mounted on the main board.

The cooling device 1000 includes a cooling fan 200 for sucking external air to discharge the sucked air, a radiant fin 140 fixed to a discharge side of the cooling fan 200 to radiate the heat, and heat pipes 150 contacting with the radiant fin 140 and extending toward the heat-generating components 160 to move the heat. The cooling fan 200 sucks external air to discharge the sucked air. Thus, the heat generated from the heat generating components 160 is moved into the radiant fin 140 through the heat pipes 150 and is cooled by the external air discharged from the cooling fan 200.

Any fan having a structure equal to that of the cooling fan 200 may be used as an air conditioner or a heater.

The cooling fan 200 according to an exemplary embodiment of the present invention may reduce noise generated at a cutoff portion 211.

The cooling fan 200 according to an exemplary embodiment of the present invention will be described in detail in FIG. 3.

FIG. 3 is an exploded perspective view of a cooling fan according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the cooling fan 200 includes a scroll housing 210 and a fan cover 230, which are coupled to each other to define a passage through which air flows.

The cooling fan 200 includes an impeller 220 including curved blades 222 that generate a pressure required for sucking the external air and discharging the indoor air. The impeller 220 is coupled with a motor 221 and is disposed inside the scroll housing 210 and the fan cover 230.

The scroll housing 210 includes a lower suction port 215 for sucking the external air and a discharge port 214 for discharging the sucked air. The scroll housing 210 has a scroll-type spread pattern in which an inner passage is gradually increased toward the discharge port 214. The fan cover 230 includes an upper suction port 232 for sucking the external air and is coupled to the scroll housing 210.

The scroll housing 210 includes the curved cutoff portion 211 adjacent to the discharge port 214 to divide an air flow.

Thus, the introduced external air is converted into air having a static pressure while the introduced external air flows along inner surfaces of the scroll housing 210 and the fan cover 230 via the curved blades 222 due to a centrifugal force generated by the impeller 220. Then, the air having the static pressure may be discharged through the discharge port 214 to achieve the desired effect.

Moreover, the scroll housing 210 may include a fan base 212 for rotatably supporting the impeller 220. In addition, a circuit board for controlling an operation of the impeller 220 is mounted on the fan base 212. The scroll housing 210 according to an exemplary embodiment of the present invention may include a lower suction interrupting part 213 for preventing air from being sucked into the neighborhood of the cutoff portion 211 through the lower suction port 215 to reduce the noise generated at the cutoff portion 211.

The fan cover 230 according to an exemplary embodiment of the present invention may include an upper suction interrupting part 231 for preventing air from being sucked into the neighborhood of the cutoff portion 211 through the upper suction port 232 to reduce the noise generated at the cutoff portion 211.

The fan cover 230 may be coupled to the scroll housing 210 using a screw-coupling, welding, or adhesion method.

Referring to FIG. 3, the cooling fan 200 embodied according to the present invention has a structure in which the external air is sucked through both sides, i.e., the upper suction port 232 and the lower suction port 215. Also, according to an exemplary embodiment of the present invention, it may prevent the external air from being sucked into the neighborhood of the cutoff portion 211 through the two suction ports 232 and 215. However, the present invention is not limited thereto and is applicable to a cooling fan having a structure in which air is sucked in one direction.

The cooling fan 200 may be generally equivalent to a centrifugal fan. The centrifugal fan includes a spiral housing such that air flows in a rotation-axis direction at an inlet side of an impeller, and the air flows in a direction perpendicular to the rotation-axis direction at an outlet side of the impeller. The centrifugal fan may be classified into a multi-blade fan (sirocco fan), a radial fan, a turbo fan, and an airfoil fan according to a configuration and structure of an impeller. Also, the centrifugal fan may use any one of the above-described fans.

In detail, the cooling fan 200 embodied in FIG. 3 may be equivalent to a both-sides suction type centrifugal fan. However, the present invention is not limited thereto and is applicable to a single-side suction type centrifugal fan.

In case of the centrifugal fan, a motor for driving the impeller may be installed outside a housing to drive the motor using a power transmission part such as a belt.

FIG. 4 is a perspective view of an assembled cooling fan according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the fan cover 230 includes the upper suction interrupting part 231 for preventing the air from being sucked into the neighborhood of the cutoff portion 211 through the upper suction port 232 to reduce the noise generated at the cutoff portion 211.

FIG. 5 is a perspective view of an assembled cooling fan according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the scroll housing 210 includes the lower suction interrupting part 213 for preventing air from being sucked into the neighborhood of the cutoff portion 211 through the lower suction port 215 to reduce the noise generated at the cutoff portion 211.

FIG. 6 is a view illustrating a change of noise values measured over a frequency band of a conventional cooling fan, and FIG. 7 is a view illustrating a change of noise values measured over a frequency band of a cooling fan according to an exemplary embodiment of the present invention.

Referring to FIGS. 6 and 7, noise values measured over frequency bands of a conventional cooling fan 100 before improvement and the cooling fan 200 improved according to an exemplary of embodiment the present invention may be compared with each other using graphs. As shown in FIGS. 6 and 7, the respective cooling fans 100 and 200 generate broad noise distributed over a broad frequency band. Specifically, the respective cooling fans 100 and 200 generate discrete frequency noise having a peak value in a specific frequency band. The conventional cooling fan 100 has peak values of about 26.72 dB (left) and about 27.84 dB (right) in a frequency band ranging from about 1,000 Hz to about 2,000 Hz. \The cooling fan 200, according to an exemplary embodiment of the present invention, has peak values of about 22.73 dB (left) and about 21.42 dB (right) in a frequency band ranging from about 1,000 Hz to about 2,000 Hz. When the peak values of the two cooling fans 100 and 200 are compared with each other, since the cooling fan 200 according to an exemplary embodiment of the present invention has a structure in which the external air is prevented from being sucked into the neighborhood of the cutoff portion 211, the cooling fan 200 generates a discrete frequency noise value lower than that of the conventional cooling fan 100.

As described above, since cooling fan 200 prevents the external air from being sucked toward the neighborhood of the cutoff portion, the noise generated during driving may be reduced.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the scope of the invention is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being included in the present invention. 

1. A centrifugal fan comprising: a housing comprising a suction port, a discharge port and a cutoff portion for dividing an air flow; a spiral impeller coupled with a motor to suck air through the suction port of the housing in a rotation-axis direction and discharge the sucked air through the discharge port in a direction perpendicular to a rotation-axis; and a suction interrupting member preventing air from being sucked into a neighborhood of the cutoff portion through the suction port, wherein the housing further comprises an outwardly curved cutoff portion at a side of the discharge port.
 2. The centrifugal fan of claim 1, wherein the suction interrupting member extends from an inner surface of the suction port adjacent to the cutoff portion in the direction perpendicular to the rotation-axis.
 3. The centrifugal fan of claim 1, wherein at least one of: one suction port and two suction ports, each facing the impeller, are provided.
 4. The centrifugal fan of claim 1, wherein an external air discharge passage of the housing has a spiral shape with respect to the rotation-axis.
 5. The centrifugal fan of claim 1, wherein the impeller comprises curved blades extending radially outward.
 6. The centrifugal fan of claim 1, wherein the motor is installed outside the housing to rotate the impeller using a power transmission unit.
 7. A computer cooling fan comprising: a housing comprising a suction port, a discharge port and an outwardly curved cutoff portion at a side of the discharge port; a spiral impeller coupled with a motor to suck air through the suction port of the housing in a rotation-axis direction and discharge the sucked air through the discharge port in a direction perpendicular to a rotation-axis; and a suction interrupting member preventing air from being sucked into a neighborhood of the cutoff portion through the suction port.
 8. The computer cooling fan of claim 7, wherein the suction interrupting member extends from an inner surface of the suction port adjacent to the cutoff portion in the direction perpendicular to the rotation-axis.
 9. The computer cooling fan of claim 7, wherein at least one of: one suction port and two suction ports, each facing the impeller, are provided.
 10. The computer cooling fan of claim 7, wherein an external air discharge passage of the housing has a spiral shape with respect to the rotation-axis.
 11. The computer cooling fan of claim 7, wherein the impeller comprises curved blades extending radially outward.
 12. A fan comprising: a housing including at least a suction port and a discharge port, said discharge port including an outwardly curved cutoff portion; a spiral impeller for draw air through the suction port in a rotation-axis direction and discharge air through the discharge port in a direction perpendicular to a rotation-axis; a motor connected to said spiral impeller for driving said impeller; and a suction interrupting member preventing air from being sucked into a neighborhood of said cutoff portion through the suction port.
 13. The fan of claim 12, wherein the suction interrupting member extends from an inner surface of the suction port adjacent to the cutoff portion in the direction substantially perpendicular to the rotation-axis.
 14. The fan of claim 12, wherein at least one of: one suction port and two suction ports, each facing the impeller, are provided.
 15. The fan of claim 12, wherein an external air discharge passage of the housing has a spiral shape with respect to the rotation-axis.
 16. The fan of claim 12, wherein the impeller comprises curved blades extending radially outward. 